Insecticides are commonly used to control populations of pests and disease vectors. However, they can have multipleunintended effects on non-target species. Assessing their impacts on the physiology and behavior of beneficial insects,such as biological control agents, is thus necessary to gain insight into the diversity and nature of such side effects.Here, we investigated the effect of sublethal doses of the endocrine disrupting insecticide pyriproxyfen, a juvenile hormoneagonist, on females of the solitary ectoparasitoid Eupelmus vuilleti (Hymenoptera: Eupelmidae). These parasitoidwasps can be used as biological control agents to control the cowpea weevil, Callosobruchus maculatus (Coleoptera:Bruchidae), that infests cowpea seeds, Vigna unguiculata (Fabacea). To do so, in addition to classical measures on femalefecundity and survival, we focused on female behaviors that can have important consequences on female fitnessand host exploitation. First, we showed that pyriproxyfen stimulated egg production without affecting female survival.Second, we observed that low doses of this insecticide had no effect on females' exploration and host discriminationability but stimulated their aggressiveness when fighting for host access. Although a negative impact on other lifehistorytraits cannot be ruled out at this point, these results showed low doses of pyriproxyfen can have unintendedpositive effects on ectoparasitoid E. vuilleti females, by enhancing at least temporarily their reproduction and host accessin a situation of competition. Our work thus highlights the importance of studying the diversity of possible unintendedsublethal effects of pesticides on beneficial insects.